Kiyomi Teramoto

Serum asymmetric dimethylarginine as a marker of coronary microcirculation in patients with non-insulin dependent diabetes mellitus: correlation with coronary flow reserve

Abnormalities of coronary microcirculation without large vessel atherosclerosis have been known in patients with non-insulin dependent diabetes mellitus (NIDDM). Coronary flow reserve (CFR) has been considered an important physiological parameter in the coronary circulation reflecting the function of large epicardial arteries and the microcirculation, including endothelial function. Reduced CFR and impaired endothelium mediated, nitric oxide dependent coronary vasodilatation1,2 have been observed in NIDDM without overt coronary artery disease. Asymmetric dimethylarginine (ADMA) is a major endogenous nitric oxide synthase inhibitor and has been considered a novel risk factor of cardiovascular disease.3 Serum or plasma concentration of ADMA is increased in patients with NIDDM3 and may attenuate vascular function. However, to our knowledge, the relation between ADMA and CFR has not been examined in patients with NIDDM. Our goal was to examine the relation between serum ADMA concentration and CFR in patients with NIDDM by means of non-invasive transthoracic Doppler echocardiography. We studied 47 patients with NIDDM without a history of cardiovascular disease. We limited our study population to non-smokers and patients treated with diet or oral hypoglycaemic agents alone. All patients underwent two dimensional echocardiography and a treadmill exercise test …

Cibenzoline improves coronary flow velocity reserve in patients with hypertrophic obstructive cardiomyopathy

The effect of cibenzoline, a class-Ia antiarrhythmic drug, on coronary flow velocity reserve (CFVR) was examined in patients with hypertrophic cardiomyopathy using transthoracic Doppler echocardiography. Coronary flow velocity reserve was assessed in 11 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 12 patients with hypertrophic nonobstructive cardiomyopathy (HNCM), before and after the intravenous administration of cibenzoline (1 mg/kg). Coronary hyperemia was induced by an intravenous infusion of adenosine triphosphate and CFVR was calculated as the ratio of hyperemic to basal mean coronary diastolic flow velocity. At baseline, CFVR was significantly correlated with left ventricular outflow tract pressure gradient (LVPG) in patients with HOCM (r = 0.67, P < 0.03). In patients with HOCM, administration of cibenzoline significantly improved impaired CFVR (2.0 ± 0.8 to 3.0 ± 1.0, P < 0.001), and reduced LVPG (55 ± 30 to 23 ± 18 mmHg, P < 0.001), while CFVR remained unchanged in patients with HNCM (2.6 ± 0.9 to 2.9 ± 0.8, P not significant). Cibenzoline not only reduces LVPG but also improves CFVR in patients with HOCM. In addition left ventricular outflow obstruction plays an important role in impaired coronary circulation in patients with HOCM.